This invention relates to apparatus for automatically opening rectangular envelopes, the top edges of which have previously been slit.
We have previously disclosed, in U.S. Pat. No. 3,691,726, entitled "Method and Apparatus for Opening Envelopes," an apparatus for automatically opening rectangular envelopes. In this apparatus, envelopes stacked initially in a feeder station are individually removed from the stack at a pick-off station located adjacent the feeder station and are moved to a top edge cutting station in which the top edge portion of the envelope is removed. The envelope is then moved through a drop chute station and is placed vertically in a V-shaped conveyor tray. The conveyor tray is advanced through an end breaking or separating station in which a pair of oppositely disposed suction cups separate the envelope sides and in which a pair of pivoted burster blades are moved downwardly into the envelope between the separated sides and outwardly against the respective side edges to break them. Finally, the envelope is moved through a sorting area in which the sides of the envelope are held open to expose the contents for removal and sorting.
Although the above-described apparatus satisfactorily achieves its objectives, it suffers an inherent design deficiency of being unable to accommodate, without readjustment, envelopes of varying sizes. That is, owing to the pivotal movement of the bursting blades in the end separating station, these blades are limited to a short stroke and the positions thereof must be readjusted to work with differently sized envelopes. In the feeder station, envelopes are maintained in an upright position by means of pairs of spaced feed dogs affixed to endless chains disposed along the sides of the envelope stack. This arrangement, of course, is operable only with envelopes having a uniform length. As a result of these limitations, time-consuming presorting is required in the usual case involving varying envelope sizes.
In addition to the foregoing the system disclosed in our prior patent is designed for multiple operator use. In the sorting area, the end-slit envelope is carried in the conveyor tray along a linear path of several tray lengths before the conveyor tray moves around an end sprocket wheel to dump the remaining tray contents into a waste receptacle. The linear layout required by the use of the conveyor trays involves a number of operators at the sorting station. Modified versions of the apparatus of our prior patent designed for single operator use have not provided adequate storage for opened envelopes to permit the operator to remove and sort the contents with ease.